The present invention relates to heat-insulating boards used as heat-insulating liners in tundish vessels and other molten metal handling vessels and other situations where heat-insulation is desired. Ordinarily, these boards are refractories of various sizes and shapes with tundish boards, for example, being 1 to 2 feet wide, 3 to 6 feet long and about 1 to 1.5 inches thick.
The tundish, for example, serves as a molten metal reservoir and in order to prevent contamination thereof the used tundish boards are replaced with new tundish boards on a periodic basis. The same is true, for example, with boards used to line ladles and other metallurgical vessels.
However, present heat-insulating boards are too brittle and tend to fracture or break in shipment or handling during use.
At the present time a variety of materials are added to standard refractory materials used to form heat-insulating boards in order to improve the handling strength thereof and in particular toughness and impact resistance. Efforts to improve such properties include imbedding wires such as chicken wire in the board during the forming process. Other materials, such as steel fibers, have been utilized, as well as paper and rock wool (mineral wool or glass wool) fibers. None of these additives however has been successful in giving the improved strength and toughness desired in order to have the board resistant to elastic deformation and crack initiation.